Paul Kirk comes to the Senate at crucial time for Democrats

Former Democratic Party chairman Paul Kirk speaks as Sen. John Kerry (D) of Massachusetts (c.) and Gov. Deval Patrick (r.) listen during a news conference at the Statehouse in Boston on Thursday, where Patrick announced that Kirk will temporarily fill the late Sen. Edward Kennedy's US Senate seat.

When Kirk takes the oath of office on Friday, the Democrats will be back to 60 votes in the 100-seat Senate – an important threshold, as 60 votes are required to halt a filibuster. If Democrats were to vote in unison on health reform – far from a sure thing – there is nothing Republicans can do to stop them.

The White House is heaving a sigh of relief that Kennedy’s seat has been filled quickly, until an election can be held Jan. 19.

The Massachusetts legislature voted to change the succession law this week, allowing Governor Patrick to name a caretaker. The Democratic-controlled legislature had changed the law under former governor Mitt Romney (R) to prevent him from appointing a Republican to the seat, in the event Massachusetts’ other senator, John Kerry (D), had been elected president in 2004.

"I am pleased that Massachusetts will have its full representation in the United States Senate in the coming months, as important issues such as healthcare, financial reform, and energy will be debated,” Obama said in a statement. “Paul Kirk is a distinguished leader, whose long collaboration with Senator Kennedy makes him an excellent, interim choice to carry on his work until the voters make their choice in January."

Democrats are now holding their breath over the faltering health of another Senate lion – 91-year-old Sen. Robert Byrd (D) of West Virginia, the longest-serving senator in history (at 50 years and counting). Earlier this week, Byrd fell in his home and was taken to a hospital, but is reportedly fine. Still, the episode served as a reminder that the Democrats’ 60-vote majority is shaky.

But as long as Byrd remains in the Senate, his ability to appear for votes is an open question. Senators must be present to vote. In July and August, Byrd missed all but two of the Senate’s roll call votes.

The timing of Senator Kennedy’s passing could not have been more poignant. Universal health coverage was Kennedy’s mission, and his dying wish was to see an appointed caretaker fill his seat in time to vote for health reform.

Kirk, a Kennedy family friend, onetime aide to the senator, and former Democratic National Committee chairman, emerged as the consensus choice by Kennedy’s widow and children. After the drama in New York and Illinois over Democratic governors’ Senate appointments, Patrick may well be breathing his own sigh of relief that selecting Kirk was made easy for him.

The Massachusetts legislature’s controversial tinkering with the law has left a sour taste in Republican mouths. But with Democrats controlling the levers of power in Massachusetts, there was nothing the GOP could do.